This invention relates, in general, to tool grinders and, more particularly, to safety rests for tool grinders.
Grinding wheels are employed in tool fabrication to smooth the surfaces of tools or parts during the fabrication of the tools or machine parts.
A typical bench grinder has one or two side-by-side, rotatable grinding wheels formed of abrasive material. A safety rest is mounted in front of each grinding wheel to provide a stationary surface for the operator to rest the part being ground.
OHSA regulation 191.215A4 requires a 1-3 mm gap between the grinding wheel and the safety rest to prevent equipment damage or bodily injury to the operator.
Typical safety rests have a straight edge facing the originally flat outer circumferential edge of the grinding wheel or a U-shaped notch in the straight edge of the safety rest which surround the originally flat front edge and a portion of the adjacent outer sides of the grinding wheel. The entire safety rest can be adjusted to maintain the required 1-3 mm spacing as the outer edge of the grinding wheel wears.
However, the notches in the safety rest have flat perpendicularly oriented sides to accommodate the original perpendicularly oriented flat sides and end surface of a new grinding wheel. The flat edge surface of the safety rest can be adjusted, as described above, relative to the grinding wheel as the flat end surface of the grinding wheel wears away in order to maintain the required 1-3 mm safety gap.
However, special shaped wheels which do not have a flat corner between the front edge and the sides of the grinding wheel or a wearing down of the originally flat corner of a grinding wheel by operators using the edge of the grinding wheel for smoothing radius cuts, etc., cause the originally flat corner edge of the grinding wheel to wear away into a curved radius. This curved radius edge on the grinding wheel becomes spaced further and further away from the corresponding inner corner edge of the safety rest as the grinding wheel edge wears away. This opens a gap larger than that required by safety regulations.
It will be desirable to provide a grinding wheel safety rest which accommodates grinding wheel edge wear or grinding wheels having special edge shapes during the useful life of the grinding wheel.